/Engine/Plugins/Online/OnlineSubsystem/Source/Public/Interfaces/OnlinePartyInterface.h
Cleanup party state. This will cleanup the local party state and attempt to cleanup party memberships on an external service if possible. Intended to be called for development purposes.
void CleanupParties ( const [FUniqueNetId](API\Runtime\CoreOnline\Online\FUniqueNetId) & LocalUserId, const [FOnCleanupPartiesComplete](API\Plugins\OnlineSubsystem\Interfaces\FOnCleanupPartiesComplete) & CompletionDelegate )